The maintenanceof effectivecognitivefunctioningacross the lifespan is a crucial componentof an individual's well-beingandability to function independentlyin society.Althoughthere isa large literatureon cognitive performancein cider adulthood,there is limited nformation about cognitivefunctioning inmidlife. The proposed research will address that need by characterizing cognition across midlife and into old age on key domains that are hypothesizedto be sensitive to age effects, including verbal memory, working memory, executive function, reasoning,and speed of processing. Cognitive testing will be carried out through telephone interviews as part of the MIDUS II study. This will create a unique opportunity to examine the performance of middle-aged adults in a large-scale, nationally representative sample. In addition, the MIDUS study will provide a rich data base that will enable us to examine the relationship betweencognitive performance and a variety of biopsychosocial factors. The goal is to identify antecedents of effective cognitive function, in order to determine those factors that may serve a protective role in maintaining mental abilities, as well as those factors that serve as risk factors for exacerbating cognitive declines. We will investigate the links between cognitive performance and variables of interest, including SES, health, control beliefs, stressful life events, and menopausal status. Specifically, we predict that cumulative advantage (including high SES, good physical and mental health status, adaptive health behaviors, low stress, and a strong sense of mastery and control) will serve as a protective buffer against age decrements in cognitive performance in midlife and later life. Conversely, we expect that cumulative adversity (including low SES, chronic poor health, limited psychosocial resources) will be associated with greater vulnerability for cognitive deficits. We also will examine whether changes associated with the menopause are related to cognitive aging. A final goal is to carry out longitudinal analyses with an oversample from the Boston area, tested in 1996 on a multi-factor cognitive battery, stress reactivity measures, and control beliefs. This will provide valuable information on how changes over time in stress and psychosocial variables impact changes in cognitive performance during midlife. Understandingthe pathways to adaptive cognitive functioning in midlife may contribute to early detection and possible prevention of aging-related cognitive decline.